Core drill



J. A. zUBLiN CORE DRILL Filed June 22, 1 936 Feb. 9, 1937.

Patented Feb. 9, 1937` oFFlca UlillTl-Lo sTTEs PATEN CORE 1| 2 l John A.Zublin, Los i n cles, Calif. Application June 22, 193e, lserial No.Asacas 12 claims. '1 (ci. 25a-71) While the present invention relatesgenerally It is a general object of my invention both to to oilwelltools, it is more especially concerned decrease the amount of activecutting area which with core -drills adapted toV operate in rock and isat any one time in cutting position, and to inother relatively hardformations, and of the type crease the amount of reserve area, with aview which remove the formation in an annular path to increasing thedrilling rate of the tool and to leave at the center of the hole a corewhich lengthening the life of the tool.

passes up between the cutting elements and It is also an object of theinvention to proenters a barrel adapted to receive the core. y vide acore drill which, in addition to the usual For reasons that are wellknown in the art, oil reserve cutting area on each cutter, has a welltools used successfully in rock and other sumciently large number ofcutters that several 10 hard formations nearly always have rotatingentire cutters are in reserve, and are, as a whole, cutters, since theyproduce the best kind of drillsuccessively brought into cutting positionand ing motion. However, -there are conflicting rethen returned to thenon-cutting position. quirementsfor best design. To secure the maxi-Another object is to provide a core drill with mum penetration of thecutters, it is necessary to rolling cutters mounted at differentpositions and 15 have only a minimum portion of the cutters indifferentangles upon a carrierl so that the cutcontact with the formation at anyone time, as ters will move witha substantially rollingl molhigherpressure per unit area increases the penetion over parts of the holelying at angles to tration of the teeth. 0n the other hand, to give eachother and the carrier, as the side and bota long life to thev tool andkeep down the cost of 'tom of the hole, so that the cutters act at all20 drilling it is necessary to provide a maximum of times at a highefciency. cutting teeth on the tool, since the life ofthe It is anotherobject of my invention to provide tool'is generally proportional to thetotal numa core drill with a plurality of rotatable cutter ber and sizeof cutting teeth available to cut the carriers rotated by their naturaltendency to formation, and an increase in the total number turn when incontact with the formation, and 25 of teeth is usually accompanied by -alike inbringing successive cutters intermittently into crease in thenumber of teeth cutting at one time. cutting contact with the formation.It becomes apparent that the ideal tool has a It is also a main objectof the invention to largetotal amount of cutting surface, but hasprovide a core drill in which removal of the only a small part of thatsurface active or in formation is done solely by roller cutters which 30drilling contact at any one time, the remainder trim the core to sizewithout the, aid of a fixed of the cutting surface being, in effect, inre annular cutter or the like. serve, since it does its share of thecutting And a further object is to provide a core after the rst activeportion moves .out of drill with. rolling cutters. which each cut on'thecontact with the formation. In reamlng tools hole sidesand bottom orwhich are divided into 35 of conventional types using roller cutters,all groups so that a portion of the cutters ream the the cutters aregenerally in simultaneous enholevside while other cutters cut on thebottom gagement with the formation, so the reserve of the hole toenlarge the hole and to trim the cutting surface is limited to thatportion of core to proper size. -1

40- each cutter not so-engaged, and amounts to but These objects areattained in a core drill .40 a few, perhaps three or four, times theactive" having a core receiving barrel by rotatably cutting surface,whereas an increase in the mounting on the drill a plurality of cuttecar-A ratio between reserve and active portions riers each with aplurality of rolling cu ters increases both the efliciency and the lifeof rotatably mounted on it. The carriers move the the tool. cutters overan annular path from which the 45 Ifamember rotatable about an axis onatool is l formation is removed and so cut a core of a brought intocontact with the formation, and the proper size to enter'the barrel.vThe carriers are tool as a whole is rotated, there is a naturaltendinclined to enable the cutters to remove formaencyY for the memberto rotate about its own axis tion to the extent required to cut thecore.`

on the tool. 'This natural tendency vis strong and Drill bits embodyingmy invention are vshown 50 positive, and will move cutters mounted onthe in my copending cases entitled Drill-bit with rotatable member intoand out of cutting enrolling cutters, Ser. No.v 56,252,"flled Decembergagement with the formation, and so bring en- 26, 1935, nowlPatent No.2,050,989,and Rotary` tire cutters intermittently into-active positiondrill bit with rolling cutters, Ser. No. 71,600,

56 from reserve. flied March 30, 1936, now Patent No. 2,050,988, 55

and these earlier cases contain claims to subject matter common to allthree cases, the claims in the present case being directed to matterpeculiar to this case alone.` j

How the above and other-objects oi' my iny i Fig. 4 is a fragmentaryview, partially in section and partially in elevation, of a variationalform of core drill. e

Referring to Figs. 1 to 3, there is shown a core drill comprising a corehead I0 having a central opening for a core to move upwardlytherethrough, and mounted on the lower end of outer barrel I|. bInsidethe outer barrel I I andattached to it is inner barrel I2 adapted toreceive and protect core I3 after it has been formed, as will be wellunderstood by those versed in the art. In order to prevent the core fromdropping out of the drill as the tool is removed from the well, corecatching means-ls provided in the form of chains I4 which wrap aroundthe core and wedge into 'the space between the core and the lowerconstricted portion of core head III. lThis core catching means isdescribed and claimed in my Patent No. 1,859,950. v

V The lower nd Aof head ,I0 is provided with a pair of integral studs I6which provide journal bearings upon whichv are rotatably mounted thecutter assemblies, generally indicated at I8. 'I'hese bearings I6 areinclined to the horizontal so that cutter assemblies I8 rotate aboutaxes which are inclined upwardly and inwardly, and are here shown asintersecting at or near the center ofthe drill. Although only two cutterassemblies are shown mounted upon the core drill, a larger numbermay beused ii' desired.

Each cutter assembly It comprises a circular. wheel-like body 20 with aplurality of roller cutters 2| rotatably mounted, in slots about thebody periphery, upon axle pins 22. The ends of pins 22 are secured tothe body by any suitable meansyas, by welding. Rolling cutters 2| may beoi.' any suitable size and shape and have any parallel tothe axis ofrevolution to the carrier and so do not intersect the carrier axis.' butlie at an 'angle thereto. Additional details of construction andvariational forms oicutter mountings are shown lin my copendingapplication, Cutter assembly for oil well tools", iiled on\even dateherewith. y

Carri` 20 is held in place on bearing Il by means o matching annulargrooves. on'e in the bearing and one in the body, which together form a'channell that holds a plurality4 of ball bearings 24, this arrangementpermitting free rotation or me body about bem-mg Il but noiaing itsecurely against axial displacement. The

lballs are held in the channel bymeans ot threaded plug25. Y

Circulation fluid passes downL -in the annular space between innerbarrel I2 and outer barrelv II, and is discharged through nozzles 21onto the rolling cutters 2| to clean them. l

Cutter assemblies |8are mounted on the outside of core head 20 androtate in an annular path from which formation is removed .by the actionof cutters 2|,- and so leave at the center of the hole core I3 which isof a size to pass upwardly through the core head and enter the barrell2. As carriers 2li rotate, the several cutters upon each carrier aresuccessively brought into intermittent contactl with the formation handcut away the formation at the sides and bottom of the hole; and sinceall the cutters are mounted in a similar manner on the carrienall thecutters operate on both the sides andbottom to keep the hole to fullgauge and to trim the core to proper' size. 'I'he planes of revolutiono! carriers 20 are inclined inwardly and downwardly so that cutters 2|are enabled to remove the formation directly underneath head and barrelI 2, and trim the core-to proper size, it being clear that, otherdimensions remaining constant, the size ofthe core will be determined bythe" inclination of the carriers. l 5 A variational form of core tool isshown Fig. 4 which vis constructed in the same manner as alreadydescribed, except that rolling cutters are mounted in a somewhatdifferent manner upon carriers. Onveach of carriers 30 a portion of thecutters are mounted on pins Il so that they rotate about radial axesperpendicular to the axis of carrier rotation. These cutters 32 projectbeyond one side of the carrier body axis of carrier rotation, and thesecutters 3l project radially beyond the carrier to remove formation atthe bottom ofthe hole as do cutters 2| inv Fig. 1. Preferably a portionol'cutters I6 are oil'set toward the outside iace oi' carrier Il -sothat they remove formation at the bottom,

oi' the hole adjacent the side walls of the hole, and thus operate to`enlarge the hole; while the remainder of cutters It are -oii'set towardthe` inner tace of carrier Il and remove formation from the bottom oithe hole adjacent core Il and so4 operatesto Atrim the core to size.Cutters may be mounted upon the same carrier-'3l inboth of these twopositions, or the cutters on one .carrier maybe connned to one positionso that theyv cut on. the bottom either near the outsidenexttothewallorneartheinsidenexttothe core. K- 4 It will be understoodthat changes may be made in the construction and the arrangement of thevarious parts without departing from the spirit and scope oi' myinvention, and it is theretore to be understoodthat the appended -claimsare illustrative o! rather vthan `restrictive l10n the broad scopeoi' myinvention.l

Iclaimasmyinvention: r

1..In acoredrill, thscombination adapted to receive a com, a pluralityo! cutter carriers rotatably mounted on the drill. rand a pluralityoifroller cutters rotatably mounted on each carrier, said carriers andcutters being .adopted toremove vformationin an annular-path oiabarrel 7I and leave a central core of proper size to enter the barrel.

2. In a core drill, the combination of a barrel adapted to receive acore, means to retain a core in the barrel, a plurality of cuttercarriers rotatably mounted on the drill, and a plurality of rollercutters rotatably mounted on each carrier, the planes of revolution ofthe carriers being inclined inwardly and downwardly so that the cuttersremove formation beneath the drill except for a central core beneath thebarrel of a size to enter the barrel.

3. In a core drill, the combination of a barrel adapted to receive acore, a plurality of cutter carriers rotatably mounted on the drill, anda plurality of toothed, substantially cylindrical roller cuttersrotatably mounted on each carrier, said carriers and cutters beingadapted to remove formation in an annular path and leave a central coreof proper size to enter the barrel.

4. In a core drill, the combination of a barrel adapted to receive acore, a plurality of cutter carriers rotatably mounted on the drill, anda plurality of roller cutters rotatably mounted on each carrier andprojecting radially beyond the carrier to remove formation beneath thecarrier, said carriers and cutters being adapted to remove formation inan annular path and leave a central core of proper size to enter thebarrel.

5. In a core drill, the combination of a barrel adapted to receive acore, a plurality of cutter carriers rotatably mounted on the drill torotate about axes inclined upwardly and inwardly,' and a plurality ofroller cutters rotatably mounted `on each carrier, said carriers andcutters being adapted to remove formation in an annular path and leave acentral core of proper size to enter the barrel.

6. In a core drill having in combination a barrel adapted to receive acore, a pair of cutter fcarriers rotatably mounted on the drill torotate about axes which are inclined upwardly and in- Wardly tointersectat the center of the drill, and a plurality of roller cuttersrotatably mounted on each carrier, said carriers and cutters beingadapted to remove formation in an annular path and leave a central.core'of proper size to enter the barrel.

7. In a core drill, the combination of a barrel adapted to receive acore, a plurality of cutter carriers rotatably mounted on the drill, anda plurality of roller cutters rotatably mounted on each carrier torevolve about axes inclined to but not intersecting the axis of carrierrotation, said carriers and cutters being adapted to remove formation inan annular path and leave a central core of proper size to enter thebarrel.

8. In a core drill, the combination of a barrel adapted to receive acore, a plurality of cutter carriers rotatably mountedpn the drill torotate about axes inclined upwardly and inwardly, and a plurality ofroller cutters rotatably mounted on each carrier to revolve about axesinclined to l but not intersecting the axis of carrier rotation, saidcarriers and cutters being adapted to remove formation in Aan annularpath and leave a central core of proper size to enter the barrel.

9. In a core drill, the combination of a barrel adapted to receive acore, a plurality of cutter carriers rotatably mounted on the drill torotatev rality of roller cutters rotatably mounted on each carrier, aportion of the cutters projecting radially beyond the carrier to removeformation at the bottom of the hole and a portion of the cuttersprojecting beyond the side of the carrier to remove formation from thesides of the hole, said carriers and cutters being adapted to removeformation in an annular path and leave a central core of proper size toenter the barrel.

l1. In a core drill, the combination of a barrel adapted to receive acore, a plurality of cutter carriers rotatably mounted on the drill, anda plurality of roller cutters rotatably mounted on each carrier to turnabout axes, part of which are parallel to the axis of carrier revolutionand part of which are perpendicular to the axis of carrier revolution,said carriers and cutters being adapted to remove formation in anannular path and leave a central core of proper size to enterv thebarrel.

12. In a core drill, the combination of a barrel adapted to receive acore, a plurality of cutter carriers rotatably mounted on the drill, anda plurality of roller cutters rotatably mounted on each carrier, saidcarriers and cutters being adapted to remove formation in an annularlpath and leave a central core of proper size to enter the barrel, aportion of the cutters projecting beyond the sides of the carrier toremove `formation from the sides of the hole by reaming, another portionof the cutters projecting radially beyond the carrier to removeformation from the bottom of the hole adjacent the sides to' enlarge thehole, and another portion of the cutters projecting radially beyond thecarrier to remove formation from the bottom of the hole adjacent thecore to trim the core to size.

JOHN A. ZUBLIN.

